• 산업기술연구
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• 제14권
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• pp.3-17
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• 1994

This paper develops a design technique for approximating nonseparable frequency characteristics by sums and products of separable transfer functions. Therefore nonseparable frequency characteristics includes the four-quadrant symmetry filters. The desired filter with half plan symmetry is obtained by shifting a low pass characteristic in the frequency domain, and by combining these shifted characteristics. Also the paper develops the technique for designing recursive and nonrecursive two dimensional digital filters by the application of a complex transformation to one dimensional low pass filter.

• ETRI Journal
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• 제29권4호
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• pp.437-444
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• 2007

A CMOS frequency synthesizer block for multi-band orthogonal frequency division multiplexing ultra-wideband systems is proposed. The proposed frequency synthesizer adopts a double-conversion architecture for simplicity and to mitigate spur suppression requirements for out-of-band interferers in 2.4 and 5 GHz bands. Moreover, the frequency synthesizer can consist of the fewest nonlinear components, such as divide-by-Ns and a mixer with the proposed frequency plan, leading to the generation of less spurs. To evaluate the feasibility of the proposed idea, the frequency synthesizer block is implemented in 0.18-${\mu}m$ CMOS technology. The measured sideband suppression ratio is about 32 dBc, and the phase noise is -105 dBc/Hz at an offset of 1 MHz. The fabricated chip consumes 17.6 mA from a 1.8 V supply, and the die-area including pads is $0.9{\times}1.1\;mm^2$.

• 대한한방소아과학회지
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• 제18권2호
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• pp.77-91
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• 2004

Objectives : In evaluating a child with enuresis, an organized approach to the history leads to a working diagnosis and an appropriate treatment plan. but, there's no study about history taking in enuretic children. This article was undertaken to evaluate the enuretic child exactly and to study nocturnal enuresis systematically. Methods : It was conducted a computerized literature search in following database: Medline (via Pubmed), NDSL, EBSCO. Korean articles via oriental pediatric association homepage, KISS. Key words to search were 'nocturnal enuresis', 'bedwetting', 'enuresis', 'incontinence', 'management', 'evaluation', 'assessment', 'questionnaire', 'guideline', 'voiding dysfunction'. Results : Questions are grouped in eight categories: primary history(sex, age, height, weight), family history, enuresis history(primary/secondary, frequency, time of enuresis, nocturia), voiding history(average number, frequency, pattern, volume, posture, daytime enuresis), medical history, constipation/encopresis, sleep(OSA). Conclusion : A careful, complete history taking will help to plan treatment properly and to study.

• 한국주거학회논문집
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• 제17권2호
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• pp.143-150
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• 2006

In this Study, it was investigated what the critical elements of the Architectural Review by the Seoul Building Design Committee were. The critical elements selected by the members of committee were systematically analyzed. They were based on the 169 cases reviewed by the Building Design Committee. The committee consists of Professors, famous architects, architectural experts and official members. Thus, the critical elements selected by the committee can be regarded as the important criteria for the forthcoming architectural reviewing process. The critical elements selected by 960 members of the committee were classified by the frequency. The results in this study showed that the critical elements were ordered as follows: (1)floor plan, (2)landscape gardening, (3)form, (4)open space, (5)structure, (6)plan for preventing disasters, (7)circulation for men and cars, (8)facilities, (9)parking, (10)revision of drawings and documents. These criteria of the architectural evaluation established by the Seoul Building Design Committee can be applied to the fundamental preparation of the architectural review.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.121-122
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• 2002

When a power system experiences a serious disturbance on insufficient power, the system frequency may drop. For system frequency will be maintain standard value, under_frequency relay will reconstruct balance of power and load by load shedding. Currently load shedding scheme is due to establishment plan by fixed scenario. Where compare current scheme with past scheme, system frequency should be recovered by load shedding using rate of frequency decline. This paper suggests the dynamic load shedding scheme by using the rate of change of frequency when The Korea Electric power system is happened the large disturbance.

• 한국치위생학회지
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• 제20권2호
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• pp.129-137
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• 2020

Objectives: Using the annual data from the 2016 Korean Health Panel, this study aims to identify the factors that affect the dental utilization and expenditure of patients with chronic diseases, and to provide basic data to explain the inequality gap in dental utilization. Methods: The dental utilization and expenditure of 3,557 patients with chronic diseases were analyzedfor frequency using the SPSS Windows version 23.0 (SPSS Inc. IL, USA). Analysis of the factors that affect dental utilization and expenditure were performed using a multiple regression analysis. The level of statistical significance was 0.05. Results: The frequency of dental utilization in patients with chronic diseases was high for subjects who were younger than 65 years and those whose education level was below high school. The frequency of dental utilization was relatively lower for subjects who did not have disabilities and those with healthier subjective health status. The dental expenditure of patients with chronic diseases was higher in subjects who were younger than 65 years and those with greater household income. Conclusions: The above findings suggest that a plan is needed to control dental utilization by efficiently managing chronic diseases, and that a policy-based plan is needed to devise ways to supplement the uninsured medical expenses of dental care.

• 전기학회논문지
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• 제60권4호
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• pp.766-770
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• 2011

In this paper, we describe the failure analysis and representation test method that applied high frequency transformer for SMPS through analysing insulation resistance, frequency characteristic, CT analysis, Q-factor atc. And we study the judgement method that a high frequency transformer affects to other beside parts in different condition or environment. According to this method, we devise a plan for the field failure prevent and propose the securing product reliability of high frequency transformer.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.849-852
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• 2007

본 논문에서는 마이크로스트립 안테나의 좁은 대역폭 문제를 개선하여 IEEE 802.11a의 표준규격(가. $5.15{\sim}5.25$[GHz], 나. 5.25${\sim}5.35$[GHz], 다. $5.725{\sim}5.875$[GHz])을 모두 포함할 수 있는 5[GHz]대역 광대역, 고 이득 안테나를 설계하였다. 설계된 패치 안테나는 소형화를 위해 분리되어진 방사패치와 기생패치 사이에 유전체(폴리우레탄 : ${\varepsilon}_r=6.5$)를 삽입하여 공진주파수를 조정하였으며, 공기에 의해 분리되어진 방사패치와 접지면을 폼(${\varepsilon}_r=1.03$)으로 고정시켰다. 설계된 안테나의 주파수 대역폭(VSWR 2:1)은 $4.9[GHz]{\sim}6.1[GHz]$까지 약1.2[GHz]의 광대역 특성을 보였으며, 또한 E-평면과 H-평면 이득은 12[dBi]이상, 3[dB] 빔폭은 E-평면 $30^{\circ}$와 H-평면 $60^{\circ}$이상의 개선된 특성을 보였다.

• Earthquakes and Structures
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• 제25권6호
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• pp.417-427
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• 2023

If the center of mass and center of stiffness or strength of a structure plan do not coincide, the structure is considered asymmetric. During an earthquake, in addition to lateral vibration, the structure experiences torsional vibration as well. Lateraltorsional coupling in asymmetric structures in the plan will increase lateral displacement at the ends of the structure plan and, as a result, uneven deformation demand in seismically resistant frames. The demand for displacement in resistant frames depends on the magnitude of transitional displacement to rotational displacement in the plan and the correlation between these two. With regard to the inability to eliminate the asymmetrical condition due to various reasons, such as architectural issues, this study has attempted to use supplemental viscous dampers to decrease the correlation between lateral and torsional acceleration or displacement in the plan. This results in an almost even demand for lateral deformation and acceleration of seismic resistant frames. On this basis, using the concept of Torsional Balance, adequate distribution of viscous dampers for the decrease of this correlation was determined by transferring the "Empirical Center of Balance" (ECB) to the geometrical center of the structure plan and thus obtaining an equal mean square value of displacement and acceleration of the plan edges. This study analyzed stiff and flexible torsional structures with one-way and two-way mass asymmetry in the Opensees software. By implementing the Particle Swarm Optimization (PSO) algorithm, the optimum formation of dampers for controlling lateral displacement and acceleration is determined. The results indicate that with the appropriate distribution of viscous dampers, not only does the lateral displacement and acceleration of structure edges decrease but the lateral displacement or acceleration of the structure edges also become equal. It is also observed that the optimized center of viscous dampers for control of displacement and acceleration of structure depends on the amount of mass eccentricity, the ratio of uncoupled torsional-to-lateral frequency, and the amount of supplemental damping ratio. Accordingly, distributions of viscous dampers in the structure plan are presented to control the structure's torsion based on the parameters mentioned.

• 대한토목학회논문집
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• 제31권3D호
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• pp.383-389
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• 2011

본 연구는 교통기본법(안)에 명시된 대중교통 사각지대 설정과 평가를 위한 3가지 평가척도를 제시하였다. 평가척도는 행정동 단위의 대중교통 노선 및 운행실태에 대한 기초 DB를 적용하여 대중교통 서비스권역, 대중교통 배차간격, 1일 총 운행시간을 각각 A-F(6등급)으로 구분하였다. 대중교통 사각지대 평가척도는 정부 및 지자체에서 대중교통 서비스 낙후지역의 최저 대중교통 공급 및 연계노선 계획, 최저배차계획, 1일 대중교통 총 운행시간 계획에 기준으로 활용할 수 있을 것이다.